Hi guys.Hope someone can help.
Recently moved in and decided to change switches and lights and forgot to remember what went where.So down stairs I have a 2 Gang 2 way switch which should control the hallway light and the landing light.Upstairs I have a 1 Gang 2 way switch.Therefore the landing light can be turned on and off from downstairs and upstairs.

I have the following wiring downstairs: 2 Reds(only 1 of these is live),2 Blacks and 2 earths.I have put the live red into common terminal and the black into L1.L2 has been left emptyThis switches the downstairs light on and off perfectly.I have then put a link wire from the first common terminal to the second common terminal and the other black into the second L1 and the other red into L2.The earths are in a seperate terminal.

Upstairs in the box I have a red and earth coming from the light and then the red,black and earth from downstairs cming up in to the box.I have wired as follows: Red from light into the common terminal,Red from downstairs into L2 and Black into L1.Earth into seperate terminal.

Wiring at ceiling where the landing light is fitted as follows: Red and Earth and then a seperate single core black wire.

Connected the above as follows: Red to live terminal on the new light and black to neutral and earth to earth terminal but it will not work.WHY?
SOMEONE PLEASE HELP!!!

I will guess it is the down-stairs switch which is wrong.
"I have then put a link wire from the first common terminal to the second common terminal"
If two way lighting then I would expect link from first common to either L1 or L2 the other one of pair should feed light. The twin would go to common and either L1 or L2 which ever has not got link in it.
Up stairs same colour wire as in common down stairs will go to common up stairs.
I would expect a link wire up-stairs also and remaining wire from down stairs goes to one without link which will also feed lamp.
Because it is now common to split up-stairs and down-stairs lights most houses have three wires between the switches and don't link the lives which will mean looking at projects page would not work for you. Also Wikipedia shows a different method to what we use. To use their method needs a connector within the switch which is why it is not used. I do have diagram on my web site but not allowed to give link sorry.